FIG. 1 is a flow chart depicting a conventional method 10 for fabricating a PMR transducer. For simplicity, some steps are omitted. FIGS. 2-5 depict a conventional PMR transducer 50 formed using the method 10 as viewed from the air-bearing surface (ABS). The conventional PMR transducer 50 is formed using the conventional method 10. The conventional PMR transducer 50 may be part of a coupled with a slider to form a conventional PMR head. In addition, a read transducer (not shown) may be included to form a merged conventional PMR head. For simplicity, only a portion of the conventional PMR transducer 50 is shown.
Referring to FIGS. 1-5, the conventional chemical mechanical planarization (CMP) support structure, conventional PMR pole layers and CMP stop layer are provided, via step 12. The conventional CMP support structures are to attempt to aid in ensuring the CMP, described below, results in a relatively planar surface. Typically, the CMP support structure is between three and five microns from the PMR pole being formed. Thus, the CMP support structure may be in the device region and near the field regions between device regions. Typically, the CMP support structures are formed by milling a portion of the PMR pole layers that have been deposited, then refilling this region with the CMP support structure material, which is typically alumina. The conventional PMR pole layers may include a seed layer and one or more layers forming the magnetic portion of the conventional PMR pole. The conventional PMR pole layers reside on an underlayer, such as aluminum oxide or other nonmagnetic material. The conventional PMR pole layer(s) include magnetic materials suitable for use in the conventional PMR transducer. The conventional CMP stop layer follows the contour of the top surfaces of the PMR pole layers and the conventional CMP support structures. The conventional CMP stop layer may include materials such as diamond-like carbon (DLC).
A conventional hard mask is provided on the conventional CMP stop layer, via step 14. The conventional hard mask covers a portion of the PMR pole layers from which the conventional PMR pole is to be formed. The conventional hard mask may include materials such as NiFe. FIG. 2 depicts the conventional PMR transducer 50 after step 14 is performed. Consequently, an underlayer 52 on which the PMR pole layers 54 and conventional CMP support structure 53 are shown. Also depicted are the conventional CMP stop layer 56 and the conventional hard mask 57.
The conventional PMR pole is defined from the conventional PMR pole layers 54, via step 16. Step 16 typically includes performing an ion mill and a pole trim using the hard mask to expose the portion of the conventional PMR pole layer(s) to be removed. FIG. 3 depicts the conventional PMR transducer 50 after step 16 has been performed. Thus, the conventional PMR pole 54′ has been formed. In addition, only a portion of the conventional CMP stop layer 56′ and conventional CMP support structure 53′ remain.
A conventional intermediate layer is provided, via step 18. The conventional intermediate layer is typically aluminum oxide that is blanket deposited on the conventional PMR transducer 50. A CMP is performed to completely remove the conventional hard mask 57, via step 20. The conventional CMP stop layer 56′ is also removed, via step 22. Thus, the top surface is formed by portions of the intermediate layer and the conventional PMR pole. A write gap is deposited on the conventional PMR transducer and a shield is provided, via steps 24 and 26, respectively.
FIG. 4 depicts a conventional PMR transducer 50 after completion. Thus, the intermediate layer 58, write gap 60, and trailing shield 62 are shown. Also shown is a notch 62 in the shield 60 due to the topology of the conventional PMR transducer 50.
Although the conventional method 10 may provide the conventional PMR transducer 50, there may be drawbacks. In particular, as the critical dimensions of structures in the conventional PMR transducer 50 shrink to accommodate higher densities, tighter control may be desired for the structures in the conventional PMR transducer 50. Conventional methods, including the conventional method 10, may not provide the desired control over at least some portions of the conventional PMR transducer 50.
For example, some methods for forming the conventional PMR transducer 50 result in variations in the height of the notch 64. In the conventional PMR transducer 50, the notch 64 juts toward the conventional PMR pole 54′. However, in some cases, removal of the conventional hard mask 57 in step 20 removes a greater portion of the intermediate layer 58. FIG. 3 depicts a conventional PMR transducer 50′ in which this has occurred. The conventional PMR transducer 50′ is analogous to the conventional PMR transducer 50 and may be formed using the conventional method 10. Thus, the conventional PMR transducer 50′ includes underlayer 52′, conventional CMP support structures 53″, conventional PMR pole 54″, intermediate layer 58′, write gap 60′, and shield 62′. Because a greater portion of the intermediate layer 58′ has been removed, the top surface of the intermediate layer 58′ is lower than the top of the conventional PMR pole 54″. Moreover, a portion of the PMR pole 54″ may be inadvertently removed. Thus, when the write gap 60′ and top shield 62′ are provided in steps 24 and 26, the notch 64′ is in the opposite direction from the notch 64. Consequently, the conventional method 10 might result in a notch 64, no notch, or a notch 64′ in the reverse direction. Further, both the notch 64 and the notch 64′ are abrupt. The conventional method for fabricating the conventional PMR transducer 50 may thus have relatively large variations in the conventional PMR transducer 50. Consequently, performance of the conventional PMR transducer 50/50′ may vary.
Accordingly, what is needed is an improved method for fabricating a PMR transducer.